The bright weekend sun brought welcome light to the city’s $9 billion restaurant business, which two weeks ago had obituary writers moving in for the kill.

The unexpected uptick came before yesterday’s U.S. attack on Taliban bases in Afghanistan – which intelligence official had earlier warned would mean “100 percent” certainty of further terrorist raids. And, the other day, The Post reported a secret plan to “lock down” the city for its own protection when the U.S. struck back.

But to the joy of the restaurant world, many Manhattan places near-empty in the weeks following the Sept. 11 World Trade Center atrocity, rallied smartly over the last five days. The weather coaxed diners out of their neighborhoods for the first time since Sept. 11, and some places that had cut workers had more business than they could handle.

At Tavern on the Green, the country’s highest-volume eatery, weekend volume was back up to 90 percent of normal, according to spokesperson Shelley Clark. Tavern served 900 dinners Saturday night and 1,000 brunches yesterday, said Clark, who reported “day-to-day improvement.”

North of SoHo, at least, signs of resurgence were everywhere. Some restaurants were offering discounts, but owners said the main reason for the turnout was that New Yorkers had “finally decided to put their grief on the shelf,” said one who did not want to be named.

On East 22nd Street, between Broadway and Park Avenue South, Friday night, every house was packed, from Commune to Beppe, where Sen. Chuck Schumer left at 8:30 to diners’ cheers.

Regina McMenamin, spokesperson for The Four Seasons, said “people came out in force mid-week,” and Saturday night was like “like December,” the busiest month.

Eateries along Broadway on the Upper West Side, including Ouest and Avenue, were jammed. So were Blue Hill and Sushi Samba 7 in the Village. At La Goulue on Madison at 62d Street, a sign announced “now hiring hosts and hostesses.”

But it was a different story below Houston Street, where four “destination” neighborhoods – SoHo, TriBeCa, Chinatown, and Little Italy – continue to suffer from limited access, and where many restaurants are fighting for their lives.

In TriBeCa, where auto traffic is still tightly restricted, David Bouley has only just reopened Bouley Bakery Restaurant and Danube. Bouley, who selflessly coordinated the effort to feed rescue workers, could not be reached. Drew Nieporent, whose Myriad Restaurant Group owns Nobu, Montrachet and others in TriBeCa, called the weekend “spectacular,” but cautioned that he was still living “day to day.”

TriBeCa Grill, Nieporent said, served 300 diners Saturday – well below the normal 400 to 500, but a big improvement over the previous week.

Since the end of the Jewish holidays – which significantly reduce restaurant-going every year, and this time coincided with the city’s mourning its 5,000-plus dead – Nieporent has reopened all Myriad’s restaurants except Layla. He would not quantify the impact of the WTC afternmath, except to say “we lost $1 million in gross sales the first two weeks. I’m just happy to stay in business.”

The boomlet has given heart to some owners who sounded ready to give up just a week earlier.

Meanwhile, hotel lobbies were busy again after weeks of near-desolation. Kathleen Duffy, a spokesperson for Marriott, which runs eight hotels in Manhattan and Brooklyn, said the 1,946-room Marriott Marquis in Times Square was “100 percent sold out” Saturday night, following a week of improvement.